iPhones with aftermarket batteries installed by third-party repair shops are now eligible for service at Genius Bars and Apple Authorized Service Providers, according to an internal Apple document obtained by MacRumors from three reliable sources.

And:

The updated guidelines went into effect Thursday and should apply worldwide. Apple will still decline service for iPhones with third-party logic boards, enclosures, microphones, Lightning connectors, headphone jacks, volume and sleep/wake buttons, TrueDepth sensor arrays, and certain other components.